A child slides down a hill on a toboggan with an acceleration of 1.8 m/s^2 . I f she starts with an initial push of 1.2 m/s , how far does she travel in 4.0 s?

A14 kg rock starting from rest free falls through a distance of 5.0 m with no air resistance. find the momentum change of the rock caused by its fall and the resulting change in the magnitude of earths velocity. earth mass is 6.0 * 10^24 kg. show your work assuming the rock earth system is closed.